The Decycler Oscillator was created by John Ehlers (Cycle Analytics For Traders pgs 43-44) and it is used to show transitions between uptrends and downtrends. If it rises above the 0 line then this means it has transitioned to an uptrend and it falls below the 0 line then it is in a downtrend. Buy if the indicator line is green and sell when it is red.
This was a custom request so let me know if you would like to see more scripts from me or if you want something custom done!